Chemical vapor deposition merges MoS 2 grains into high-quality and centimeter-scale films on Si/SiO 2 .

Two-dimensional molybdenum disulfide (MoS 2 ) has attracted increasing attention due to its promise for next-generation electronics. To realize MoS 2 -based electronics, however, a synthesis method is required that produces a uniform single-layer material and that is compatible with existing semiconductor fabrication techniques. Here, we demonstrate that uniform films of single-layer MoS 2 can be directly produced on Si/SiO 2 at wafer-scale without the use of catalysts or promoters. Control of the precursor transport through oxygen dosing yielded complete coverage and increased connectivity between crystalline MoS 2 domains. Spectroscopic characterization and carrier transport measurements furthermore revealed a reduced density of defects compared to conventional chemical vapor deposition growth that increased the quantum yield over ten-fold. To demonstrate the impact of enhanced scale and optoelectronic performance, centimeter-scale arrays of MoS 2 photosensors were produced that demonstrate unprecedentedly high and uniform responsivity. Our approach improves the prospect of MoS 2 for future applications.